Friction draft-gear.



G. WESTINGHOUSE.

FRICTION DRAFT GEAR.

APPLICATION FILED NOV. 28. 1906.

Patented Jan. 18, 1916. 7

GEORGE WESTINGHOUSE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTING-HOUSE AIR BRAKE COMPANY, PITTSBURGH, PENNSYLVANIA, A CORPORATION.

OF PENNSYLVANIA.

FRICTION DRAFT-GEAR.

To all whom it may concern:

Be it known that I, GEORGE WESTING- HOUSE, a citizen of the UnitedStates, residing at Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented new and useful Improvements in FrictionDraft-Gear, of which the following is a specification;

This invention relates to yielding resistance mechanism for transmittingstresses be tween members having a limited relative movement, and isparticularly adapted to be,

applied as a railway draft and buffing appliance for transmitting draftand bufling strains between the draw bar and the framing of the car ortruck and for absorbing and dissipating the sudden shocks and jars towhich the draft rigging is subjected in the ordinary running andshifting of rail- Wa cars.

' he object of my present invention is to is a longitudinal section of ayielding resistance mechanism embodying my improvements; Fig. 2 an endview of the same showing a part of the springrbroken away; Fig. 3 anelevation of a portion of the helical resistance spring; and Fig; 4: aninside view of a portion of one of the segmental friction strips,looking in the direction of the arrow, (Fig. 2) and showing the helicalpro ection for engaging the beveled surface on one of the coils of thespring.

According to my improvement, as shown in the drawing, a coiled spring 5,which is preferably substantially helical, has formed upon one of itsturns or coils, or a portion thereof, a beveled surface 6, which isinclined relatively to the longitudinal axis of the spring. This beveledsurface may be formed in any suitable manner, and at any Specificationof Letters Patent.

Patented Jan. in, 1916.

Serial No. 345,422.

desired point upon the spring, but accordmg to the preferredconstruction, this beveled surface is formed by cutting away a portlonof the metal upon the outer side of one of the intermediate turns orcoils of the spr ng. In this way one portion" of the spr ng may be madeto act as apreliminary reslstance and the other part as a main re sstance spring in conjunction with the frictional resistance.

A plurality of friction strips, or segments, 7, extendinglongitudinally, are mounted upon the outside of the coiled spring, andeach segment isprovided upon its inner side wlth a projection 8, in theform of a part of a helix adapted to extend in between two adjacentcoils of the spring, and also having one face formed as an inclined orwedging surface 9 for engaging with the beveled surface 6 on the spring.The outer or frictional surface 10 of the segments may be of any desiredform, but is preferably V-shaped in cross-section; that is, formed withfaces arranged at an angle to each other and extending outward from theaxis of the spring to meet and form a longitudinal edge.

The coiled spring, with its friction segments, is surrounded by andinclosed in a metal casing 11, which 1mav be of any deslred shape incross-section, and is provided with inside frictional surfaces 12 forcocperating with the frictional surfaces of the segments. As shown inthe drawing, only four frictional segments are employed, and the anglebetween the outer friction faces is substantially 90, so that in thiscase the casing is substantially square in its cross-sectional outline.A difi'erent number of segments may, however, be employed, if desired,and the angle between the outer friction faces may be varied to give agreater or lesser amount of wedging action, and consequently I vary theamount of frictional resistance exerted between the friction faces'ofthe segments and the corresponding frictional surfaces of the casing.The casing is made somewhat shorter than the spring coil to allow forthe maximum movement in the compression of the mechanism, and the friconits inner face varies in the successive segmentsto correspond: with thepitch of the helical spring, so that the outer ends of the segments willbe in the same transverseplane, and the spring is prevented from turningor shifting. its pos1tion n the segments by shoulders of the pro ectionsengaging the notched portion of the spring.

When my improved yielding resistance mechanism is used as a frictiondraft gear, it is applied between the follower plates of the draftriggingof a railway car and the draft and buiiing stresses which aretransmitted from the draw bar cause the movement of'one of the followerplates toward the other and the compression of the resistance spring. Asthe spring begins to compress, it naturally first yields at its thesurfaces on the inside of the casing,v

thereby creating sufficient frictional resistance, which in connectionwlth the reslstance of the other or main portion of the spring, servesto hold the segments from sliding to any great extent until the outerend portion of the spring is compressed to the point of allowing thefollower plate to bear against the ends of the segments. In this mannerthe portion of the spring from the weak coil outward constitutes apreliminary resistance spring, which acts to resist and transmit theminor shocks and stresses without causing a frictional sliding movementof the segments and a compression of the other or main portion of thespring. In the case of the larger stresses and shocks, the followermoves farther inward forcing the segments to slide into the casing andcompressing the main portion ofv the resistance spring, thereby exertingthe combined action of the spring and the fric'-' tional'resistancebetween the segments and the inner frictional surfaces of the casing forabsorbing'andtransmitting the stresses. If desired,'the casing may bemade slightly tapering, in order to increase the frictional resistancebetween the segments and the easing as the segments are forced inward.Then when the follower starts outward, as stresses is being relieved,the coils of the outer portion of the spring begin to expand and relievethe pressure upon the wedge surfaces of'the coil and the projections ofthe segments, whereupon the expansion of the main portion of the springoperates to effect a smooth and complete release of the frictionsegments and to force the same back to their normal position.

Having now described myinventiomwhat I claim as new and desire tosecureby Letters Patent, is

1. A yielding resistance mechanism comprising a continuous helicalresistance spring having one only of its intermediate coils partly cutaway to form a weakened portion of less cross-sectional area than theremainder of the spring, and provided with an inclined wedging surface,a member having a vcorresponding wedging surface for engaging therewith,and means cooperating with said member for producing frictionalresistance.

2. A yielding resistance mechanism comprising a continuous resistancespring having one of'its intermediate coils of less cross-see tionalarea and weaker than the, remainder of. the spring, and provided with aninclinedwedging surface, a plurality of longitudinal segments eachhaving a projection provided with a corresponding wedging surface forcotiperating with the inclined surface of the coil, and meanscooperating with said segment for producing frictional resistance.

- 3. A'yielding resistance mechanism-comprising a c ontinuousresistance. spring having one "only ofits intermediate coils providedwith an inclined wedging surface, a plurality of longitudinal segmentshaving helical projections provided with, corresponding wedging surfacesand extending between the adjacent coils of the spring whereby theexpansion of the spring operates to release the segments, andmeans'cooperating with said segments for producing frictionalresistance.

In testimony whereof I have hereunto set my hand. 1

GEO. WESTINGHOUSE. Witnesses:

H. C. TENER,

GEO. V. MILLIGAN,

